44&#39;-dibrom-diphenyl-disulfid-2.2&#39;-dicarboxylic acid and process of obtaining such bodies.



' UNITED STATES PAEENT OFFICE.

, nnunnn MfiNCH, or nUnwmsHArEN-oN-THE-mrmn, cnnmnnvfnssren'o n Tonanrscnn nnrnm & SODA rannrx, or LUDWIGSHAFEN-ON-THE-RHINE, GER.-

MANY, A CORPORATION.

4.4'-DIBROltI-DIPHENYL-DISULFID-2.2'-DICARBOXYLIC ACID AND PROCESS OF iOBTAINING SUCH BODIES. i v

No Drawing. I

To all whom 'it may concern:

Be it known that I, EnUARn Mt'iNoH, doctor of philosophy and chemist,subject of the Grand Duke of Baden, residing atLudwigshafen-on-the-Rhine, Germany, have invented new and usefulImprovements in 4.4 Dibrom-Diphenyl-Disulfid-2.2' Dicarboxylic 'Acid andProcesses of Obtaining.

such Bodies, ofxwhich the following is a specification.

I have discovered a new body suitable for the manufacture of coloringmatters which is chemically a 4.4-dibrom-diphenyl disul--fid-2.2-dicarboxylic acid, and toobtain my new body I have discovered anew process which can also be applied by the production of analogousbodies. I have discovered that by reacting with a solution of asulfanti-.

moniate, sulfars'enate, or sulfostannate'or an orthodiazobenzoic acidcompound, 'under' which term I include orthodiazo-ben'zoic acid itself,or a homologue, or an analogue,thereof, or a derivative of eitherof'these' compounds, the corresponding' diphenyl-disulfid-2.2'-'dicarboxylic acid compounds are obtained in a pure condition,theyield being almost quantitative. Apparently intermediate compoundscontaining bothsulfur and a diazo group are formed, but these are veryunstable and immediately begin to split u giving rise to the diphenl-disulfid-2.2-d 1- carboxylic acid compoun s. For the purpose ofthisinvention a sulfarsenate and a fid-2.2'-dicarboxylic acid compoundsthus. obtained with a reducing agent, the corre sulfostannate areequivalents of a sulfantimoniate. Upon treating thediphenyl-disulsponding phenyl mercaptan 2 carboxylic acid'compounds canbe obtained. The sulfid (for lnstance theantimony pentasulfid) which isset free during the reaction can bethe like, be converted into the'sulfo salt which can then be used over again. Better yields have beenobtained when using sulfantimoniate according to this invention thanhave been obtained when using either sulfarsenia-te or sulfostannate,and the antimony sulfid formed whenfisulfoantimoniate is used can bemore easily recovered than.

can be the arsenic sulfid or the tin sulfid Specification of LettersPatent." Patented Sept. 12, 1911. I Application filed November 9, 1908.Serial No. 461,783.

formed when sulfa-rseniate or sulfostannate in twenty-four hundred partsof water and two hundred and thirty-five parts of thirt five per, cent.caustic soda solution. one hundred and forty-four parts of sodiumnitrite and allow-the solution to run, while stirring, intoa mixture offour hundred and sevent parts of thirty-two per cent.

hydrochloric acid and-eight hundred parts of ice. Then run the solutionof 2-diazo-5- brom-benzoic acid, thus obtained, into a solution ofseven' hundred parts of Schlippes salt (sodium sulfantimoniateNa",SbS,.9H,O) in five thousand parts of water, maintaining thetemperature just below zero' centigrade .and' preferably introducing thediazo solu-. 'tion intofthe antimoniatesolutionbeneath I its surface.Antimony; pentasulfid with generally. a little antimony trisulfid. isset ree, nitrogen is evolved, and a yellow solution is formed whichshould be allowed to stand, at ordinary temperature, for about from twoto three hours, until a test portion, on filtering, yields a filtratewhich is not yellow. Then acidfy the solution with hydrochloric acid andallow itto stand for about an hour and filter oil and wash theorange-yellow precipitate. 'Then stir this precipitate with about fivethousand parts of water, add one hundred and thirty parts of ammoniumcarbonate and warm on the water-bath until all" the4.4-dibrom-diphenyl-disulfid-2.2-dicarboxylic acid is dissolved andfilter off the antimony sulfid which remains undissolved. Then acidifythe filtrate with hydrochloric acid, whereupon 4.4-dibrom-diphenyluisulfid-2.2-dicarboxylic acid (IIOOH COOH I WU U.

is precipitated in the form of a white precipitate which can be filteredofi', washed and dried. The yield is almost quantitative. Since2-diazo-5-brom-benzoic acid is unstable and should not be kept for anylength of time before acting upon it with sodium sulfantimoniateaccording to this example, I have for the sake of convenience describedabove how the said diazo compound can beobtained, but the production ofthe 2-diazo- 5-brom-benzoic acid does not form any part of my invention.Similarly I have for the sake of convenience described how the 4.4-dibrom diphenyl disulfid 2.2-dicarboxy1ic acid can be isolated after ithas been formed, but such isolation does not constitute a part of myinvention.

.-My process can be applied in a similar manner to other derivatives ofanthranilic acid besides brom-anthranilic acid and to anthranilic aciditself, such ,for instance as chlor-anthranilic acid andmethyl-anthranilic acid, and in each case the correspondingdiphenyl-disulfid-2.2-dicarboxylic acid compound is obtained.

. My new. 4.4-dibrom-diphenyl-disulfid 2.2'-dicarboxylic acid ossessesthe followgrade, and when freshly precipitated from its solutions iseasily soluble in acetone and diflicultly soluble in alcohol and glacialacetic acid and very diflicultly soluble in boiling water. Now whatLclaim is 1. As a new product4.4'-dibrom-diphenyl-disulfid-22'-dicarboxylic acid which can beobtained by treating diazotized 5- brom-2-am1no-benzo'1c acld withsodium sulfantimoniate and which is colorless,

melts at about 310 0., and when freshly precipitated from its solutionis easily soluble in acetone and difiicultl soluble in alcohol andglacial acetic aci and very difficultly soluble in boiling water.

2. The process of producing4.4'-dibromdiphenyl-disulfid-2.2'-dicarboxylic acid compounds byreacting with a sulfantimoniate on a 2-diazo-5-brom-benz0ic acidcompound.

3. The process of producing a diphen ldisulfid-2.2'-dicarboxylic acidcompound y reactingv with a sulfantimoniate on an orthodiazo-benzoicacid.

. In testimony whereof I have hereunto set my hand in the presence oftwo subscribing WltIlGSSGS,

EDUARD MllNCH.

